Control device and method for outdoor fan of air conditioner

ABSTRACT

The present disclosure discloses a control device for an outdoor fan of an air conditioner. The device includes: an outdoor environment temperature detection unit configured to detect an outdoor environment temperature; a first temperature detection unit and a second temperature detection unit configured to detect an outdoor condenser coil temperature; a calculation unit configured to calculate a target rotational speed of the outdoor fan according to the outdoor environment temperature and the outdoor condenser coil temperature; and a control unit configured to control the outdoor fan to operate at the target rotational speed. The present disclosure further discloses a control method for an outdoor fan of an air conditioner.

CROSS-REFERENCE TO RELATED APPLICATIONS

The application is based upon and claims priority to Chinese Patent Application No. 201710312578.4, filed May 5, 2017, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to the field of air conditioner technologies, and more particularly, to a control device and method for an outdoor fan of an air conditioner.

BACKGROUND

Chinese Patent Application No. 201310100919.3, entitled “CONTROL CIRCUIT AND CONTROL METHOD FOR AN OUTDOOR FAN OF AIR CONDITIONER AND AIR CONDITIONER”, discloses a control method for an outdoor fan. In this solution, an outdoor condenser coil temperature is obtained by a condenser coil temperature detection unit when the outdoor fan operates, and the outdoor condenser coil temperature is compared with a preset reference temperature to determine a wind speed of the outdoor fan.

In the solution, a data collection point is single and a control manner is single. When the unique temperature detection unit fails, there is a potential risk that an operation of the air conditioner cannot be controlled.

SUMMARY

Embodiments of the present disclosure provide a control device and method for an outdoor fan of an air conditioner, and are intended to solve problems that the data collection point is single, the control manner is single, and the operation of the air conditioner cannot be controlled when the unique temperature detection unit fails in prior solutions. The following briefly describes the embodiments of the present disclosure in order to provide a basic understanding of some aspects of the present disclosure. This brief description is not intended as an extensive overview. It is not intended to identify key or critical elements, or to delineate a scope of protection of these embodiments. Its purpose is merely to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.

According to a first aspect of the embodiments of the present disclosure, there is provided a control device for an outdoor fan of an air conditioner, including: an outdoor environment temperature detection unit configured to detect an outdoor environment temperature; a first temperature detection unit and a second temperature detection unit configured to detect an outdoor condenser coil temperature; a calculation unit configured to calculate a target rotational speed of the outdoor fan according to the outdoor environment temperature and the outdoor condenser coil temperature; and a control unit configured to control the outdoor fan to operate at the target rotational speed.

Optionally, the calculation unit calculates the target rotational speed of the outdoor fan according to the following formula:

$n = \frac{N*\left( {{{Ta}\; 0} + 273.15} \right)*\left( {{{Tp}\; 0} - {{Ta}\; 0}} \right)*\left( {273.15 + {{Tp}\; 0}} \right)}{\left( {{Tp} - {Ta}} \right)*\left( {273.15 + {Tp}} \right)*\left( {273.15 + {Ta}} \right)}$

wherein n is the target rotational speed of the outdoor fan, N is a rated maximum rotational speed when the outdoor fan operates at full speed, Tp0 is an outdoor condenser coil temperature preset by the air conditioner, Ta0 is an outdoor environment temperature preset by the air conditioner, Tp is the outdoor condenser coil temperature, and Ta is the outdoor environment temperature.

Optionally, the outdoor condenser coil temperature is a higher one of outdoor condenser coil temperatures detected by the first temperature detection unit and the second temperature detection unit.

Optionally, the control unit is further configured to control the outdoor fan to operate at a first rotational speed within a first set time after startup.

According to a second aspect of the embodiments of the present disclosure, there is provided a control method for an outdoor fan of an air conditioner, including: when it is detected that an outdoor environment temperature is less than a first set temperature, controlling the outdoor fan to operate at a target rotational speed of the outdoor fan determined according to the outdoor environment temperature and an outdoor condenser coil temperature detected by a first temperature detection unit and a second temperature detection unit within a second set time; and when it is detected that an absolute value of a difference between the outdoor condenser coil temperature and a preset outdoor condenser coil temperature is greater than a second set temperature, controlling the outdoor fan to operate at a target rotational speed of the outdoor fan determined according to a latest read outdoor environment temperature and the outdoor condenser coil temperature detected by the first temperature detection unit and the second temperature detection unit within the second set time.

Optionally, the controlling the outdoor fan to operate at a target rotational speed of the outdoor fan determined according to the outdoor environment temperature and an outdoor condenser coil temperature detected by a first temperature detection unit and a second temperature detection unit within a second set time includes: calculating the target rotational speed of the outdoor fan according to the following formula:

$n = \frac{N*\left( {{{Ta}\; 0} + 273.15} \right)*\left( {{{Tp}\; 0} - {{Ta}\; 0}} \right)*\left( {273.15 + {{Tp}\; 0}} \right)}{\left( {{Tp} - {Ta}} \right)*\left( {273.15 + {Tp}} \right)*\left( {273.15 + {Ta}} \right)}$

wherein n is the target rotational speed of the outdoor fan, N is a rated maximum rotational speed when the outdoor fan operates at full speed, Tp0 is an outdoor condenser coil temperature preset by the air conditioner, Ta0 is an outdoor environment temperature preset by the air conditioner, Tp is the outdoor condenser coil temperature, and Ta is the outdoor environment temperature; and controlling the outdoor fan to operate at the target rotational speed within the second set time.

Optionally, the outdoor condenser coil temperature is a higher one of outdoor condenser coil temperatures detected by the first temperature detection unit and the second temperature detection unit.

Optionally, the method further includes: reading the outdoor environment temperature and the outdoor condenser coil temperature once every second set time, and ending after reading six groups of data; and calculating an average value of the outdoor environment temperature and an average value of the outdoor condenser coil temperature.

Optionally, the method further includes: controlling the outdoor fan to operate at a first rotational speed within a first set time after startup.

The technical solution provided by the embodiments of the present disclosure has the following beneficial effects:

the target rotational speed of the outdoor fan is determined by the detected outdoor environment temperature and the outdoor condenser coil temperature, thereby realizing a multi-unit control of the outdoor fan of the air conditioner; since an outdoor condenser is provided with two temperature detection units, sampling points of the outdoor condenser coil temperature are increased, and a potential risk that the operation of the air conditioner cannot be controlled due to a damage of a single detection unit is avoided.

It should be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not intended to limit the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this description, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

FIG. 1 is a block diagram illustrating a control device for an outdoor fan of an air conditioner according to an exemplary embodiment.

FIG. 2 is a flowchart illustrating a control method for an outdoor fan of an air conditioner according to an exemplary embodiment.

FIG. 3 is a flowchart illustrating a control method for an outdoor fan of an air conditioner according to an exemplary embodiment.

FIG. 4 is a flowchart illustrating a method for determining a target rotational speed of an outdoor fan according to an exemplary embodiment.

DETAILED DESCRIPTION

The following description and accompanying drawings fully illustrate the specific implementation solutions of the present disclosure so that a person skilled in the art can practice them. The embodiments merely represent possible changes. Unless otherwise specified explicitly, the individual component and function are optional and the operation sequence may be changed. Parts and characteristics of some implementation solutions may be included in or replace parts and characteristics of other implementation solutions. The scope of the implementation solutions of the present disclosure includes the whole scope of the claims and all available equivalents of the claims. As used herein, each implementation solution may be independently or generally expressed by “present disclosure”, which is merely for convenience. As a matter of fact, if more than one disclosure is disclosed, it does not mean that the scope of the application is automatically limited to any single disclosure or disclosure concept. As used herein, terms such as “first” and “second” are merely for distinguishing one entity or operation from another entity or operation and do not require or imply any actual relationship or sequence among these entities or operations. Moreover, terms such as “comprise” and “include” or any other variants indicate a non-exclusive inclusion, so that a process, method or device including a series of elements not only include these elements, but also include other elements not explicitly listed. Without further restrictions, the element defined by the statement “includes a/an . . . ” does not exclude the existence of other identical elements in the process, method or device that includes the element. As used herein, each embodiment is described progressively, and contents focally described in each embodiment are different from those in other embodiments. The same or similar parts among each of the embodiments may be referred to each other. Regarding a structure, a product and the like disclosed in the embodiments, since they are corresponding to parts disclosed in the embodiments, their description is relatively simple and relevant contents can be referred to the description in the method part.

FIG. 1 is a schematic structural diagram illustrating a control device for an outdoor fan of an air conditioner according to an embodiment of the present disclosure. As shown in FIG. 1, the device includes: an outdoor environment temperature detection unit 101, a first temperature detection unit 102, a second temperature detection unit 103, a calculation unit 104 and a control unit 105.

The outdoor environment temperature detection unit 101 is configured to detect an outdoor environment temperature.

The first temperature detection unit 102 and the second temperature detection unit 103 are disposed at different positions on a surface of an outdoor condenser, and both of which are configured to detect a temperature of the outdoor condenser. Since the sampling points of the outdoor condenser coil temperature are increased, a potential risk that the operation of the air conditioner cannot be controlled due to the failure of a single temperature detection unit is avoided. In this embodiment, the first temperature detection unit 102 and the second temperature detection unit 103 are respectively disposed at upper and lower positions of the condenser. In some embodiments, the first temperature detection unit 102 and the second temperature detection unit 103 are respectively disposed at left and right sides of the condenser. In other embodiments, the first temperature detection unit 102 and the second temperature detection unit 103 are respectively disposed at the upper position and the left side.

The calculation unit 104 is configured to calculate a target rotational speed of the outdoor fan according to the outdoor environment temperature detected by the outdoor temperature detection unit 101 and the outdoor condenser coil temperature detected by the first temperature detection unit 102 and the second temperature detection unit 103.

The control unit 105 is configured to control the outdoor fan to operate at the target rotational speed of the outdoor fan calculated by the calculation unit 104.

According to the device provided by the present embodiment, the target rotational speed of the outdoor fan is determined by the detected outdoor environment temperature and the outdoor condenser coil temperature, thereby realizing a multi-unit control of the outdoor fan of the air conditioner; since an outdoor condenser is provided with two temperature detection units, sampling points of the outdoor condenser coil temperature are increased, and a potential risk that the operation of the air conditioner cannot be controlled due to a damage of a single detection unit is avoided.

In other embodiments, the control device for the outdoor fan of the air conditioner includes: an outdoor environment temperature detection unit 101, a first temperature detection unit 102, a second temperature detection unit 103, a calculation unit 104 and a control unit 105.

The outdoor environment temperature detection unit 101 is configured to detect an outdoor environment temperature.

The first temperature detection unit 102 and the second temperature detection unit 103 are disposed at different positions on a surface of the outdoor condenser, and both of which are configured to detect a temperature of the outdoor condenser.

The calculation unit 104 is configured to calculate a target rotational speed of the outdoor fan according to the following formula:

$n = \frac{N*\left( {{{Ta}\; 0} + 273.15} \right)*\left( {{{Tp}\; 0} - {{Ta}\; 0}} \right)*\left( {273.15 + {{Tp}\; 0}} \right)}{\left( {{Tp} - {Ta}} \right)*\left( {273.15 + {Tp}} \right)*\left( {273.15 + {Ta}} \right)}$

wherein n is the target rotational speed of the outdoor fan, N is a rated maximum rotational speed when the outdoor fan operates at full speed, Tp0 is an outdoor condenser coil temperature preset by the air conditioner, Ta0 is an outdoor environment temperature preset by the air conditioner, Tp is the outdoor condenser coil temperature, Ta is the outdoor environment temperature, 273.15 is the lowest temperature of thermodynamics, and the unit of thermodynamic temperature scale is Kelvin.

The outdoor condenser coil temperature is a higher one of outdoor condenser temperatures detected by the first temperature detection unit 102 and the second temperature detection unit 103.

The control unit 105 is configured to control the outdoor fan to operate at the target rotational speed of the outdoor fan calculated by the calculation unit 104. The control unit 105 is further configured to control the outdoor fan to operate at a first rotational speed within a first set time after startup. The first set time has a range of 1 to 5 minutes. In this embodiment, the first set time is 2 minutes. Before controlling the rotational speed of the outdoor fan according to the outdoor condenser coil temperature and the outdoor environment temperature, the outdoor fan operates for 2 minutes, so that the temperature of the outdoor condenser tends to be stable and convenient to control. The first rotational speed is the rated maximum rotational speed when the outdoor fan operates at full speed, which ensures that the outdoor fan operates smoothly after startup; in addition, an excessive current of the outdoor fan will damage a motor when startup at a low rotational speed.

According to the device provided by the present embodiment, the target rotational speed of the outdoor fan is determined by the detected outdoor environment temperature and the outdoor condenser coil temperature, thereby realizing a multi-unit control of the outdoor fan of the air conditioner; since an outdoor condenser is provided with two temperature detection units, sampling points of the outdoor condenser coil temperature are increased, and a potential risk that the operation of the air conditioner cannot be controlled due to a damage of a single detection unit is avoided.

In other embodiments, the calculating, by the calculation unit 104, the target rotational speed of the outdoor fan according to the outdoor environment temperature and the outdoor condenser coil temperature includes the following steps. Firstly, the outdoor environment temperature and the outdoor condenser coil temperature are collected, the outdoor environment temperature and the outdoor condenser coil temperature are read once every third set time, and the step ends after reading six groups of data. The third set time is 30 seconds, and the temperature is read once every 30 seconds, thereby improving the efficiency of controlling the rotational speed of the outdoor fan while increasing the number of samples. The outdoor environment temperature is detected by the outdoor environment temperature detection unit 101, and the outdoor condenser coil temperature is detected by the first temperature detection unit 102 and the second temperature detection unit 103. A higher one of temperatures detected by the first temperature detection unit 102 and the second temperature detection unit 103 in each of the six groups of data is taken as the outdoor condenser coil temperature. After collecting the outdoor environment temperature and the outdoor condenser coil temperature, an average value of the outdoor environment temperature and an average value of the outdoor condenser coil temperature are calculated, and the target rotational speed of the outdoor fan is calculated according to the following formula based on the average value of the outdoor environment temperature and the average value of the outdoor condenser coil temperature:

$n = \frac{N*\left( {{{Ta}\; 0} + 273.15} \right)*\left( {{{Tp}\; 0} - {{Ta}\; 0}} \right)*\left( {273.15 + {{Tp}\; 0}} \right)}{\left( {{Tp} - {Ta}} \right)*\left( {273.15 + {Tp}} \right)*\left( {273.15 + {Ta}} \right)}$

wherein n is the target rotational speed of the outdoor fan, N is a rated maximum rotational speed when the outdoor fan operates at full speed, Tp0 is an outdoor condenser coil temperature preset by the air conditioner, Ta0 is an outdoor environment temperature preset by the air conditioner, Tp is the outdoor condenser coil temperature, Ta is the outdoor environment temperature, 273.15 is the lowest temperature of thermodynamics, and the unit of thermodynamic temperature scale is Kelvin.

FIG. 2 is a schematic diagram illustrating a control method for an outdoor fan of an air conditioner according to an embodiment of the present disclosure. As shown in FIG. 2, the method includes the following steps.

Step S201, when it is detected that an outdoor environment temperature is less than a first set temperature, the outdoor fan is controlled to operate at a target rotational speed of the outdoor fan determined according to the outdoor environment temperature and an outdoor condenser coil temperature detected by a first temperature detection unit and a second temperature detection unit within a second set time.

When it is detected that the outdoor environment temperature is less than the first set temperature, the calculation unit calculates and determines the target rotational speed of the outdoor fan according to the outdoor environment temperature detected by an outdoor environment temperature detection unit and the outdoor condenser coil temperature detected by the first temperature detection unit and the second temperature detection unit, and the control unit controls the outdoor fan to operate at the target rotational speed within the second set time. The first set temperature is determined according to an average value of an environment temperature of an air conditioner installation environment, and in this embodiment, the first set temperature is 35. The second set time has a range of 3 to 10 minutes, and in this embodiment, the second set time is 5 minutes. In a third set time, the outdoor fan operates stably at a currently calculated target temperature. When the outdoor fan operates stably at the currently calculated target temperature for the second set time, it is determined whether the rotational speed of the outdoor fan needs to be adjusted, thereby ensuring stable and effective operation of the air conditioner, and avoiding frequent adjustment of the outdoor fan.

Step S202, when it is detected that an absolute value of a difference between the outdoor condenser coil temperature and a preset outdoor condenser coil temperature is greater than a second set temperature, the outdoor fan is controlled to operate at a target rotational speed of the outdoor fan determined according to a latest read outdoor environment temperature and the outdoor condenser coil temperature detected by the first temperature detection unit and the second temperature detection unit within the second set time.

The air conditioner is preset with an outdoor condenser coil temperature. The outdoor fan operates stably at the currently calculated target temperature for the second set time. When the absolute value of the difference between the detected outdoor condenser coil temperature and the preset outdoor condenser coil temperature is less than or equal to the second set temperature, the outdoor fan operates stably at the currently calculated target temperature; when the absolute value of the difference between the detected outdoor condenser coil temperature and the preset outdoor condense coil temperature is greater than the second set temperature, the calculation unit calculates and determines the target rotational speed of the outdoor fan again according to the outdoor environment temperature detected by the outdoor environment temperature detection unit and the outdoor condenser coil temperature detected by the first temperature detection unit and the second temperature detection unit in the state, and the control unit controls the outdoor fan to operate at the latest calculated target rotational speed within the second set time.

According to the method provided by the present embodiment, the control unit controls the outdoor fan to operate at the target rotational speed of the outdoor fan determined by the detected outdoor environment temperature and the outdoor condenser coil temperature, thereby realizing a multi-unit control of the outdoor fan of the air conditioner; since an outdoor condenser is provided with two temperature detection units, sampling points of the outdoor condenser coil temperature are increased, and a potential risk that the operation of the air conditioner cannot be controlled due to a damage of a single detection unit is avoided.

FIG. 3 is a schematic diagram illustrating a control method for an outdoor fan of an air conditioner according to an embodiment of the present disclosure. As shown in FIG. 3, the method includes the following steps.

Step S301, the outdoor fan is controlled to operate at a first rotational speed within a first set time after startup.

A control unit controls the outdoor fan to operate at the first rotational speed within the first set time after startup. The first set time has a range of 1 to 5 minutes. In this embodiment, the first set time is 2 minutes. Before controlling the rotational speed of the outdoor fan according to an outdoor condenser coil temperature and an outdoor environment temperature, the outdoor fan operates for 2 minutes, so that the temperature of the outdoor condenser tends to be stable and convenient to control. The first rotational speed is a rated maximum rotational speed when the outdoor fan operates at full speed, which ensures that the outdoor fan operates smoothly after startup; in addition, an excessive current of the outdoor fan will damage a motor when startup at a low rotational speed.

Step S302, when it is detected that the outdoor environment temperature is less than a first set temperature, the outdoor fan is controlled to operate at a target rotational speed of the outdoor fan determined according to the outdoor environment temperature and the outdoor condenser coil temperature detected by a first temperature detection unit and a second temperature detection unit within a third set time.

When the outdoor fan operates for the first set time of 2 minutes and it is detected that the outdoor environment temperature is greater than or equal to the first set temperature, the outdoor fan continues to operate at the current first rotational speed; when it is detected that the outdoor environment temperature is less than the first set temperature, a calculation unit calculates and determines the target rotational speed of the outdoor fan according to the outdoor environment temperature detected by an outdoor environment temperature detection unit and the outdoor condenser coil temperature detected by the first temperature detection unit and the second temperature detection unit, and the calculation formula is as follows:

$n = \frac{N*\left( {{{Ta}\; 0} + 273.15} \right)*\left( {{{Tp}\; 0} - {{Ta}\; 0}} \right)*\left( {273.15 + {{Tp}\; 0}} \right)}{\left( {{Tp} - {Ta}} \right)*\left( {273.15 + {Tp}} \right)*\left( {273.15 + {Ta}} \right)}$

wherein n is the target rotational speed of the outdoor fan, N is a rated maximum rotational speed when the outdoor fan operates at full speed, Tp0 is an outdoor condenser coil temperature preset by the air conditioner, Ta0 is an outdoor environment temperature preset by the air conditioner, Tp is the outdoor condenser coil temperature, Ta is the outdoor environment temperature, 273.15 is the lowest temperature of thermodynamics, and the unit of thermodynamic temperature scale is Kelvin. The outdoor condenser coil temperature is a higher one of outdoor condenser temperatures detected by the first temperature detection unit and the second temperature detection unit. The control unit controls the outdoor fan to operate at the target rotational speed within a second set time.

Step S303, when it is detected that an absolute value of a difference between the outdoor condenser coil temperature and the preset outdoor condenser coil temperature is greater than a second set temperature, the outdoor fan is controlled to operate at the target rotational speed of the outdoor fan determined according to a latest read outdoor environment temperature and the outdoor condenser coil temperature detected by the first temperature detection unit and the second temperature detection unit within the second set time.

The outdoor condenser coil temperature is the higher one of the outdoor condenser coil temperatures detected by the first temperature detection unit and the second temperature detection unit.

According to the method provided by the present embodiment, the control unit controls the outdoor fan to operate at the target rotational speed of the outdoor fan determined by the detected outdoor environment temperature and the outdoor condenser coil temperature, thereby realizing a multi-unit control of the outdoor fan of the air conditioner; since an outdoor condenser is provided with two temperature detection units, sampling points of the outdoor condenser coil temperature are increased, and a potential risk that the operation of the air conditioner cannot be controlled due to a damage of a single detection unit is avoided.

In other embodiments, according to the control method for the outdoor fan of the air conditioner, the controlling, by a control unit, the outdoor fan to operate at a target rotational speed of the outdoor fan determined according to an outdoor environment temperature and an outdoor condenser coil temperature detected by a first temperature detection unit and a second temperature detection unit within a third set time includes the following steps.

Step S401, the outdoor environment temperature and the outdoor condenser coil temperature are read once every third set time, and the step ends after reading six groups of data.

The third set time is 30 seconds, and the temperature is read once every 30 seconds, thereby improving the efficiency of controlling the rotational speed of the outdoor fan while increasing the number of samples. In the six groups of data, each group of data includes the outdoor environment temperature detected by the outdoor environment temperature detection unit and the outdoor condenser coil temperature detected by the first temperature detection unit and the outdoor condenser coil temperature detected by the second temperature detection unit.

Step S402, a higher one of outdoor condenser coil temperatures detected by the first temperature detection unit and the second temperature detection unit is taken as the outdoor condenser coil temperature.

In the read six groups of data, each group of data includes two outdoor condenser coil temperatures, and the higher one of the two outdoor condenser coil temperatures is taken as an effective value of the outdoor condenser coil temperature to calculate the rotational speed of the outdoor fan.

Step S403, an average value of the outdoor environment temperature and an average value of the outdoor condenser coil temperature are calculated.

The average value of the outdoor environment temperature and the average value of the outdoor condenser coil temperature in the six groups of data are calculated.

Step S404, the target rotational speed of the outdoor fan is calculated according to the average value of the outdoor environment temperature and the average value of the outdoor condenser coil temperature.

According to the average value of the outdoor environment temperature and the average value of the outdoor condenser coil temperature, the target rotational speed of the outdoor fan is calculated by the following formula:

$n = \frac{N*\left( {{{Ta}\; 0} + 273.15} \right)*\left( {{{Tp}\; 0} - {{Ta}\; 0}} \right)*\left( {273.15 + {{Tp}\; 0}} \right)}{\left( {{Tp} - {Ta}} \right)*\left( {273.15 + {Tp}} \right)*\left( {273.15 + {Ta}} \right)}$

wherein n is the target rotational speed of the outdoor fan, N is a rated maximum rotational speed when the outdoor fan operates at full speed, Tp0 is an outdoor condenser coil temperature preset by the air conditioner, Ta0 is an outdoor environment temperature preset by the air conditioner, Tp is the outdoor condenser coil temperature, Ta is the outdoor environment temperature, 273.15 is the lowest temperature of thermodynamics, and the unit of thermodynamic temperature scale is Kelvin.

Step S405, the outdoor fan is controlled to operate at the target rotational speed.

The control unit controls the outdoor fan to operate at the calculated target rotational speed.

According to the method provided by the present embodiment, the target rotational speed of the outdoor fan is determined by the detected outdoor environment temperature and the outdoor condenser coil temperature, thereby realizing a multi-unit control of the outdoor fan of the air conditioner; since an outdoor condenser is provided with two temperature detection units, sampling points of the outdoor condenser coil temperature are increased, and a potential risk that the operation of the air conditioner cannot be controlled due to a damage of a single detection unit is avoided.

It should be understood that, the present disclosure is not limited to the flowchart and structures described above and shown in the accompanying drawings, and various modifications and changes may be made without departing from the scope. The scope of the present disclosure is limited only by the appended claims. 

1. A control device for an outdoor fan of an air conditioner, comprising: an outdoor environment temperature detection unit configured to detect an outdoor environment temperature; a first temperature detection unit and a second temperature detection unit configured to detect an outdoor condenser coil temperature; a calculation unit configured to calculate a target rotational speed of the outdoor fan according to the outdoor environment temperature and the outdoor condenser coil temperature; and a control unit configured to control the outdoor fan to operate at the target rotational speed.
 2. The device according to claim 1, wherein the calculation unit calculates the target rotational speed of the outdoor fan according to the following formula: $n = \frac{N*\left( {{{Ta}\; 0} + 273.15} \right)*\left( {{{Tp}\; 0} - {{Ta}\; 0}} \right)*\left( {273.15 + {{Tp}\; 0}} \right)}{\left( {{Tp} - {Ta}} \right)*\left( {273.15 + {Tp}} \right)*\left( {273.15 + {Ta}} \right)}$ wherein n is the target rotational speed of the outdoor fan, N is a rated maximum rotational speed when the outdoor fan operates at full speed, Tp0 is an outdoor condenser coil temperature preset by the air conditioner, Ta0 is an outdoor environment temperature preset by the air conditioner, Tp is the outdoor condenser coil temperature, and Ta is the outdoor environment temperature.
 3. The device according to claim 1, wherein the outdoor condenser coil temperature is a higher one of outdoor condenser coil temperatures detected by the first temperature detection unit and the second temperature detection unit.
 4. The device according to claim 1, wherein the control unit is further configured to control the outdoor fan to operate at a first rotational speed within a first set time after startup.
 5. A control method for an outdoor fan of an air conditioner, comprising: when it is detected that an outdoor environment temperature is less than a first set temperature, controlling the outdoor fan to operate at a target rotational speed of the outdoor fan determined according to the outdoor environment temperature and an outdoor condenser coil temperature detected by a first temperature detection unit and a second temperature detection unit within a second set time; and when it is detected that an absolute value of a difference between the outdoor condenser coil temperature and a preset outdoor condenser coil temperature is greater than a second set temperature, controlling the outdoor fan to operate at a target rotational speed of the outdoor fan determined according to a latest read outdoor environment temperature and the outdoor condenser coil temperature detected by the first temperature detection unit and the second temperature detection unit within the second set time.
 6. The method according to claim 5, wherein the controlling the outdoor fan to operate at a target rotational speed of the outdoor fan determined according to the outdoor environment temperature and an outdoor condenser coil temperature detected by a first temperature detection unit and a second temperature detection unit within a second set time comprises: calculating the target rotational speed of the outdoor fan according to the following formula: $n = \frac{N*\left( {{{Ta}\; 0} + 273.15} \right)*\left( {{{Tp}\; 0} - {{Ta}\; 0}} \right)*\left( {273.15 + {{Tp}\; 0}} \right)}{\left( {{Tp} - {Ta}} \right)*\left( {273.15 + {Tp}} \right)*\left( {273.15 + {Ta}} \right)}$ wherein n is the target rotational speed of the outdoor fan, N is a rated maximum rotational speed when the outdoor fan operates at full speed, Tp0 is an outdoor condenser coil temperature preset by the air conditioner, Ta0 is an outdoor environment temperature preset by the air conditioner, Tp is the outdoor condenser coil temperature, and Ta is the outdoor environment temperature; and controlling the outdoor fan to operate at the target rotational speed within the second set time.
 7. The method according to claim 5, wherein the outdoor condenser coil temperature is a higher one of outdoor condenser coil temperatures detected by the first temperature detection unit and the second temperature detection unit.
 8. The method according to claim 6, further comprising: reading the outdoor environment temperature and the outdoor condenser coil temperature once every second set time, and ending after reading six groups of data; and calculating an average value of the outdoor environment temperature and an average value of the outdoor condenser coil temperature.
 9. The method according to claim 5, further comprising: controlling the outdoor fan to operate at a first rotational speed within a first set time after startup.
 10. The device according to claim 2, wherein the outdoor condenser coil temperature is a higher one of outdoor condenser coil temperatures detected by the first temperature detection unit and the second temperature detection unit.
 11. The method according to claim 6, wherein the outdoor condenser coil temperature is a higher one of outdoor condenser coil temperatures detected by the first temperature detection unit and the second temperature detection unit. 